1. Field of the Invention
Embodiments of the present invention relate to a mobile telecommunication system. More particularly, embodiments of the present invention relate to a data transmission on a medium access control (MAC) layer.
2. Background of Related Art
A medium access control (MAC) layer of IMT-2000 may be coupled to a physical (PHY) layer, a radio link control (RLC) layer, and a radio resource control (RRC) layer. The MAC may transmit data generated from a plurality of upper layers to a lower layer through an allocated transport channel. More specifically, the MAC may select a suitable transport channel for a data transmission request of each upper layer. The MAC may efficiently allocate a transmission amount to a plurality of logical channels mapped with a transport channel.
Each of the plurality of logical channels mapped with the one transport channel may have a priority. The MAC may perform a transport format combination (TFC) selection process in which data of the logical channel having a highest priority is transmitted. The TFC of the MAC layer may be controlled by the RRC layer.
Retransmission requests may be sent when all the data has not been properly transmitted. However, in disadvantageous arrangements, data at a specific logical channel may not respond to a re-transmission request and therefore the transmitting system may become deadlocked.